In this scenario, you are a sales manager and you must assign your sales staff by customer and product category.

Drag over cells to select them (doesn't work in FF if the cell is empty). You can also select using shift-click and ctrl-click.
Ctrl-click cannot be used to select in Safari or Opera because this is the combination to invoke the context menu on those browsers.

Once some cells are selected, right-click (ctrl-click in Opera or Safari) to select an employee from the pop-up menu.

The selection will be filled with the selected employee. Notice that the
employee names and selections scroll with the grid.